1. Technical Field
The present invention relates to a radiographic image capture device, and in particular to a radiographic image capture device in which a radiation detection panel and a signal processing board are connected together by a flexible substrate.
2. Related Art
Radiation detectors are being implemented such as Flat Panel Detectors (FPDs) that convert radiation directly into digital data using a radiation sensitive layer disposed on a Thin Film Transistor (TFT) active matrix substrate. In radiographic image capture devices employing such radiation detectors, images can be more immediately checked than with radiographic image capture devices employing conventional X-ray film and imaging plates. Moreover, with such radiographic image capture devices there is the capability for fluorography (video imaging) in which successive capture of radiographic images is performed.
There are various types of such radiation detectors proposed. For example, in a radiation detector employing an indirect conversion method, radiation is converted into light by a scintillator, then the converted light is further converted into charges by sensor portions such as photodiodes. These charges are captured imaging data obtained by X-rays. In such a radiographic image capture device, the charges that have been converted by the radiation detector are read as analogue signals, and then these analogue signals are converted into digital data by an analogue-to-digital (A/D) converter after being amplified by amplifiers.
An X-ray image detector is described in Japanese Patent Application Laid-Open (JP-A) No. 2011-128000 that includes an X-ray detection panel and a circuit board, provided at the face of the X-ray detection panel on the opposite side to the X-ray incident face, that are connected together by a flexible substrate. A flexible substrate bends around from an end portion of the X-ray detection panel and is connectable to an end portion of the circuit board, resulting in a high degree of freedom for wiring. Chip On Film (COF) types of flexible substrate are being employed in which an integrated circuit, such as a gate driver and integrating amplifier, is mounted to a central portion of the flexible substrate.
When an integrated circuit (electronic component) with an analogue-to-digital conversion processing function is mounted to a flexible substrate, it is beneficial for condensers (electronic components) to be mounted to the flexible substrate in the vicinity of the integrated circuit. The condensers are electrically connected in parallel across a power source that supplies the integrated circuit, and have the function of smoothing condensers that reduce power noise. Plural condensers are mounted. The condensers mounted at positions in the vicinity of the integrated circuit are present in a high wiring density region where many signal lines connected to the integrated circuit are disposed and are connected across the power source. The condensers mounted at positions away from the integrated circuit are laid to avoid the condensers mounted at positions in the vicinity of the integrated circuit and are connected across the power source. The power source is present in a low wiring density region.
Positional adjustment of the radiographic image detector with respect to the investigation subject (patient) and adjustment of the posture of the investigation subject is performed during, or just prior to, X-ray imaging. An external force is imparted to the radiographic image detector if during this process the investigation subject makes contact with or hits the radiographic image detector, and deformation and vibration arise from the external force due to the flexibility of the flexible substrate. The deformation amount and vibration amplitude of the flexible substrate is exacerbated by the weight of the integrated circuit in cases in which the flexible substrate is a COF type.
Hence although the deformation amount and vibration amplitude of the flexible substrate is suppressed by the rigidity of the wiring lines in high wiring density regions of the flexible substrate, the deformation amount and vibration amplitude is increased in the low wiring density regions of the flexible substrate, with this being a cause of damage such as creasing or severing of the wiring lines. In cases in which damage such as creasing or severing of power supply lines occurs, faults occur in operation of the analogue-to-digital converter driven by the power source, and radiographic image data output through the analogue-to-digital converter is lost. Namely, this is a cause of line defects due to loss of radiographic image data of detection lines of the radiation detection panel connected to the analogue-to-digital converter.